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#include "ImguiParams.h"

ConstantBuffer<ImguiRendererParams> paramsIn;

RWStructuredBuffer<uint> tileCountOut;
RWStructuredBuffer<uint> totalCountOut;

#include "ImguiBlockScan.hlsli"

[numthreads(256, 1, 1)]
void main(uint3 dispatchThreadID : SV_DispatchThreadID)
{
	int tidx = int(dispatchThreadID.x);
	uint threadIdx = uint(tidx) & 255u;

	uint accumIdx = 0u;
	for (uint passIdx = 0u; passIdx < paramsIn.numTileBucketPasses; passIdx++)
	{
		uint tileBucketIdx = (passIdx << 8u) + threadIdx;

		uint bucketValue = (tileBucketIdx < paramsIn.numTileBuckets) ? tileCountOut[tileBucketIdx + paramsIn.tileLocalTotalOffset] : 0u;

		uint scanVal = blockScan(threadIdx, bucketValue);
		uint allocIdx = scanVal - bucketValue;

		if (tileBucketIdx < paramsIn.numTileBuckets)
		{
			tileCountOut[tileBucketIdx + paramsIn.tileGlobalScanOffset] = allocIdx + accumIdx;
		}

		GroupMemoryBarrierWithGroupSync();

		accumIdx += stotalCount;
	}

	if (threadIdx == 0u)
	{
		totalCountOut[0u] = accumIdx;
	}

	// temp feedback
	//totalCountOut[1u + tidx] = tileCountOut[tidx + paramsIn.tileNumTrianglesOffset];
}